"Nasal congestion, I’ve learned in all this, is far weirder than I ever thought."

"For starters, the nose is actually two noses, which work in an alternating cycle that is somehow connected to our armpits.... Each nostril opens into its own nasal cavity, which does not connect with the other directly. They are two separate organs, as separate as your two eyes or your two ears.... [T]he nose’s hidden inner anatomy is... lined with venous erectile tissue that has a 'similar structure to the erectile tissue in the penis'... Infection or allergies amplify the swelling, so much so that the nasal passages become completely blocked. This swelling, not mucus, is the primary cause of a stuffy nose, which is why expelling snot never quite fixes congestion entirely.... In healthy noses, the swelling and unswelling of nasal tissue usually follows a predictable pattern called the nasal cycle. Every few hours, one side of the nose becomes partially congested while the other opens.... Once you’re aware of the nasal cycle, you can control it—to some extent.... [T]urning from side to side [in bed]... activat[es] receptors under [you] arm, which open the opposite side of the nose.... And an online hack for stuffy noses suggests squeezing a bottle under the opposite arm...."

From "Everything I Thought I Knew About Nasal Congestion Is Wrong/Start with this: You really have two noses" (The Atlantic).